Plastic drum with removable cover and locking ring

ABSTRACT

The neck portion, extending above the bead of a plastic drum, is provided with an in-bulging section adjacent its top, to form an annular bead of smaller diameter than the neck, and with a plurality of circumferentially spaced, out-bulging extensions, each of which has a lower surface slanting upward away from the neck. A tightly fitting cylindrical cover, which is not quite as long as the neck, and fits over the latter, has a recessed top and a lip-like reinforcement extending downward from the underside of the recessed top to form an annular groove of such width as to accommodate the bead on the neck of the drum. The cover has cut out portions through which the bulge-like extensions protrude and reinforcing extensions at the lower extremities of the remaining segments. These extensions have upper surfaces slanting away from the cover at such an angle that, with the lower surfaces of adjacent bulges on the neck, they define an acute angle. A spring steel locking ring engages these surfaces to draw the cover down tight about the neck and seal the drum.

United States Patent [191 Hammes 1 PLASTIC DRUM WITH REMOVABLE COVER AND LOCKING RING [76] Inventor: Wilhelm Hammes, I-lauptstrasse' 38,

5203 Much, Germany [22] Filed: Nov, 14, 1973 [2l]'- Appl. No.: 415,539

[30] Foreign Application Priority Data Nov. 27, 1972 Germany 2258096 [52"] USYCIYQLTIQ 523 0755320742C/220/356 [51] I Int. CL... A47j 27/08, A47j 36/10, B65d 45/00 [58] Field of Search 220/55 AN, 55 R, 59, 60, 220/42 A, 42 C Primary ExaminerGeorge E. Lowrance Attorney, Agent, or FirmBurns, Doane, Swecker & "m

Mathis Dec. 3, 1974 5 7 ABSTRACT The neck portion, extending above the bead of a plastic drum, is provided with an in-bulging section adjacent its top, to form an annular bead of smaller diameter than the neck, and with a plurality of circumferentially spaced, out-bulging extensions, each of which has a lower surface slanting upward away from the neck. A tightly fitting cylindrical cover, which is not quite as long as the neck, and fits over the latter, has a recessed top and a lip-like reinforcement extending downward from the underside of the recessed top to form an annular groove of such width as to accommodate the bead on the neck of the drum. The cover has cut out portions through which the bulge-like extensions protrude and reinforcing extensions at the lower extremities of the remaining segments. These extensions have upper surfaces slanting away from the cover at such an angle that, with the lower surfaces of adjacent bulges on the neck, they define an acute angle. A spring steel locking ring engages these surfaces to draw the cover down tight about the neck and seal the drum.

PLASTIC DRUM WITH REMOVABLE COVER AND LOCKING RING BACKGROUND OF THE INVENTION Open head drums made of plastics are in widespread use for many different filling materials. In Germany, every year several million pieces are produced. The known embodiments of these drums, however, have serious disadvantages. In particular, the problem of closing a large opening in an absolutely tight and safe manner to withstand the various stresses during storage and transportation has not been solved satisfactorily so far.

One known embodiment uses a sheet steel which is. placed on the drum cover placed on and secured with a U- or V-shaped locking ring, as has been the practice for a long time in the case of drums with covers made of steel sheet. This solution is completely unsatisfactory because the relatively elastic body of the plastic drum is not compatible with the rigid cover and because the smallest deformation of the edge of the drum leads to leaks or to release of the lock.

German Pat. No. 2,008,111 describes another open head drum that is closed with a plastic cover having a large undercut which engages a corresponding bead on the head of the drum and which additionally is tied together with a locking band. In that case, the gasket is located below an additional undercut at the outside of the bordure of the drum. This embodiment results in sufficient safety against stresses during transportation, but it also has very serious disadvantages. Where the closure is a so-called snap cover, the cover must be made of soft plastic since the large undercuts, which are necessary for the function, would not otherwise permit closing and opening of the drum by hand. Since the gasket rests on the outside of 'the bordure of the drum which, due to the manufacturing process is not completely even and has a rough surface, a high contact pressure must be produced in order to achieve a sufficient tightness. This contact pressure can only be produced by placing the plastic material of the head of the drum and of the cover under tension. The well known plastic long-term deformation of thermoplastics under tension (cold flow) leads to a rapid relaxation of the closing tension and thus to a leak. This process is accelerated by the tendency of the soft cover material to rapid cold flow.

Furthermore, the use of a soft cover for the drum does not permit stacking of such drums with the customary palettes. Since the pressure of the runners of the palettes is not distributed evenly over the surface of the cover, these runners will imprint themselves in the soft cover and will not find sufficient resistance in the far blown out bordure of the drum because of its reduced wall thickness resulting from the method of production. The cover and the bordure of the drum become partially deformed and the drum becomes leaky and unusable. The use of special double side palettes,

to be sure, can partially solve this problem, but it is not economically justifiable.

MAIN OBJECTIVES AND SUMMARY OF THE INVENTION A principal objective of the present invention is to provide a plastic drum which can be closed safely and tightly with a cover made of rigid plastic.

/ ment on the underside of the cover.

Still another object is to provide a cover which can be held in place by tension which will not relax with lapse of time.

These and other objects which will become apparent to those skilled in the art are achieved by means of the invention described below and in the accompanying drawings.

In accordance with a preferred embodiment of the present invention, a plastic drum is provided with an elongated neck parallel to the center axis of the drum and which extends upward from the top of the drum. Adjacent its upper edge, the neck bulges inward to form an annular bead of smaller diameter than that of the neck. The neck is further provided with a plurality of circumferential bulge-like projections between the just described bead and the top of the drum.

The upper edge of the neck is preferably a flat surface in a plane perpendicular to the axis of the drum and neck. Considering the neck to extend vertically from the top of the drum, it may be said that the flat upper surface of the neck is horizontal.

A cover, slightly shorter than the neck of the drum, has a recessed bottom and a brim which fits over the neck. The brim, which is perpendicular to the bottom of the cover, is divided into segments. On its underside, the cover has a lip-like reinforcing extension perpendicular to the recessed bottom. The outside surface of lip-like reinforcement, together with the inner surface of the brim of the cover, forms an annular groove into which a gasket is placed. When the cover is in place, the neck of the drum is inside the annular groove and the bead on the neck fits against the lip-like reinforce- As already indicated, the cover has a brim which is divided into segments. The brim is cut away between the segments to permit the bulge-like projections on the neck to extend past the cover. At the lower edge of each of the segments, the brim has a reinforcing extension which is provided with a downwardly and outwardly extending surface. Each of the bulge-like projections on the neck has a lower surface which extends outwardly and upwardly away from the neck. These surfaces (those on the neck and those on the cover) serve as alternate supports for a locking ring which is releasably clamped around the neck of the drum and the segments of the brim of the cover.

As already mentioned, the bead of the drum, in accordance with the present invention, is formed into a vertical neck which is somewhat longer than the segments of the brim of the cover. At its lower edge, the neck merges with the body of the drum, while its upper end is formed into flat surface, preferably horizontal with respect to the neck. That is to say, the flat surface lies in a plane which is perpendicular to the axis of the drum and neck. The inwardly bulging bead below the edge of the neck fits against the outside of the lip-like reinforcement on the underside of the cover.

This lip-like reinforcement, which is preferably made integral with the cover, extends perpendicularly inward from the upper rim which surrounds the recessed bottom of the cover. The rim is ofv such width that the dimensions of the bottom of the resulting annular groove correspond to that of the previouslymentioned gasket, and when thecover isin place, the inner surface of the bead on the neck of the drum fits tightly against the outer surface of the lip-like extension on the underside of the coverQAs a result, the opening of the drum and of the neck are stabilized against deformation of their shape due to mechanical influences. Moreover, the downwardly extending lip-like reinforcement limits the actual bottom of the cover which is surrounded above by the rounded, integral rim and by the integral brim of the cover which extends perpendicularly downward from the rim.

Referring once more to the cover according to the present invention, the groove which is formed by the brim and the lip-like reinforcement extends up to the rounded rim which surrounds the bottom of the cover. A gasket, which is round or rectangular in its cross section and which consists of an elastically deformable material such as, for example, rubber, is inserted into this groove. The width of this gasket is advantagesouly selected so that it is a little larger than the distances of the lateral walls limiting the groove. When putting on the cover, the upper edge of the drum slides into the groove and fits with its upper flat frontal surface against the gasket. In the case of blown bodies of drums, in particular, this frontal surface is completely even and smooth, since it remains as a cut surface after cutting off of the excess from the body of the drum. As a result of the rectangular configuration of the reinforcement surrounding the bottom of the cover, any hollow space between the neck of the drum and the cover will be largely avoided. Consequently, the gasket is fixed in its position and there is no possibility for escape of contents from the drum in the event of stresses.

The brim of the cover, directed vertically, encircles the neck of the drum from the outside with as tight a fit as possible. Thus, the bottom of the cover merges into the upwardly curved rim which ,encloses the groove with the gasket. The rim finally ends in the brim of the cover which, up to about half of its height, still has no notches or other openings. Only that lower part of the brim of the cover which extends to the closing edge is subdivided into segments. The overall height of the brim of the cover advantageously is to be more than the height of the lip-shaped reinforcement on the underside of the cover and somewhat less than the height of the neck of the drum.

The segments on the lower half of the brim are spaced equally from one another. The width of the dis tance from one segment to another advantageously is approximately equal to" the width of one segment. The openings lying between the segments are limited by the almost perpendicular lateral edges of the adjoining segments, which then pass over in abulge into the lower edge of the brim of the cover.

Each of the segments of the brim of the cover has on its underedge a reinforcement projecting outward which advantageously is integral with said segment. The reinforcement can, in its length, project beyond the width of the segment. In this case, however, it is desirable for the small frontal surfaces of the reinforcement facing'the intervals between the segments to be 1 The upper surface of each such reinforcement can advantageously be bulged slightly outward on inward and- /or constitute an obtuse angle with the vertical line. In

the case of the present embodiment in particular, the upper surface is slanted downward and outward.

As already described, the neck of the drum is provided witha plurality of circumferentially spaced bulge-like projections. These projections extend outwardly through the cut out spaces between the segments of the brim of the cover. These projections should always be of such size and form that they will almost completely fill the space between the segments and, as far as their height is concerned, will project out of it. However, it will be of particular advantage that, whenever the projections which bulge outward on the neck of the drum completely fill the length, they also should fill the width of the space between segments of the cover.

Of importance is the arrangement, in relation to one another, of the upper surface of the reinforcements which project outwardly on the lower edge of the segments and of the lower surfaces of the projections which bulge outwardly from the neck of the drum. It is also important that, when the drum is closed, the upper surfaces of the reinforcements lie a little below the surfaces of the projections. Since these surfaces serve alternately as supports for the locking ring, distance between them advantageously should be smaller than the largest width of the locking ring measured parallel to the axis 'of the drum. Especially whenever these surfaces are formed as slants facing one another or as bulges, they are supposed to be disposed in such a way that, in its loose state, the locking ring already rests on these surfaces and will pull the cover of the drum downward with increasing tension. At the same time, not only are the segments of the cover pressed solidly against the outside surfaces of the neck of the drum, but the cover is also pulled onto the neck of the drum to such a point that the upper end or frontal surface of the neck is pressed solidly against the gasket inserted into the annular groove of the cover. In order to facilitate placing the locking ring, it is advantageous for the reinforcements on the lower edges of the cover segments to project a little farther from the lower edge of the segments than the bulge-like projections on the neck of the drum.

By arranging the upper surfaces of the reinforcements of the segments a little bit below the lower sur faces of the bulge-like projections of the neck of the downward by the lower surface of the bulge-like projections on the neck of the drum. As a result of these two oppositely directed pulling forces, a wave-shaped elastic deformation of the locking ring is produced.

To draw the locking ring tight, its ends are connected by means of a customary clamping lock. Such clamping locks, which are shortened in their length by reversing a lever or tightening a screw, are well known to those skilled in this art and need not be described here in detail. By shortening the length of the clamping lock, the circumference of the locking ring is made smaller by so much that the locking ring will rest firmly on the upper surfaces of the reinforcements of the segments and the lower surfaces of the projections of the neck of the drum and will be pulled under traction into the groove or angle defined alternately by these surfaces. The spring steel wire deformed in the shape of waves during this process counteracts with its spring force the pressure of the upper surfaces of the reinforcements of the segments in just the same way as it counteracts the pressure of the lower surfaces of the projections of the neck of the drum. Thus, the spring force of the material of the locking ring exerts a constant pull on the brim of the cover directed toward the bottom of the drum, and thus constantly presses its gasket against the completely flat upper surface of the neck of the drum. The contact pressure will remain even if a nonlasting deformation of the barrel occurs which can be caused by a mechanical effect such as, for example, a stroke, drop, or pressure during storage. Above all, however, this spring force is able to compensate for the cold flow occurring in the material of the cover and of the drum and thus keeps the drum tight even for a prolonged time.

THE DRAWINGS In order that the invention may be more readily understood, reference is now made to the accompanying drawings which depict a preferred embodiment and in which:

FIG. 1 represents a vertical section, taken on line l1 of FIG. 2, and shows the internal construction and arrangement of a portion of the assembled neck and cover;

FIG. 2 represents an elevation of an assembled neck and cover; and

FIG. 3 is a plane view of the same general area covered by FIG. 2.

DETAILED DESCRIPTION Referring to FIG. I, it will be seen that body 1 of the drum is provided with a neck 2 forming one piece with said body. Neck 2 has a bead 3 bulging inwardly and projections 4 bulging outwardly. The cover 20, shown in place on neck 2 of the drum, has a drawn-in or recessed cover bottom 5 and a rim 6 surrounding the bottom on the edge. The cover, on its underside, is provided with a lip-like reinforcement 7 which fits against the bulge of the head 3. The lip-like reinforcement 7 and the brim 8, which is perpendicular in relation to the bottom 5 of the cover, enclose and define a groove 9 in which a gasket 10 is placed. Gasket 10 is pressed against the upper surface of the neck 2 of the drum. As seen in FIG. 1, but particularly in FIGS. 2 and 3, brim 8 of the cover, in its lower part, is divided into segments 11, which encompass the bulged projections 4 of the neck of the drum. Each segment 11, at its lower end, has a reinforcement 12 projecting outwardly, the upper surface of which, together with the lower surface of the projection 4, serves alternately as a support for locking ring 13.

Referring now to FIGS. 2 and 3, it is seen that the reinforcements 12, in length, project over the widthof the segments 11, whereby the frontal surfaces 14 and 15 facing the spaces between the segments are formed slanted. Together with the peripheral edge 16 of the reinforcement l2, edges 14 and 15 individually enclose acute angles. In FIG. 2, furthermore, the wave-shaped deformation of the locking ring 13 under closing tension is shown.

SUMMARY OF ADVANTAGES Plastic drums, according to this invention, can be made from extrudeable plastics such as, for example, polyolefines. At the same time, it is of special advantage that the body of the drum and the cover can be made from the same material and with approximately the same thickness of wall. Thus, since the body and the cover of the drum have the same physical and mechnical properites, there will be no differences in the thermal and mechanical properties of the body and the cover of the drum, as in the case of the hitherto known plastic drums described initially. By the combined effect and arrangement of the locking ring with the reinforcements of the segments and the projections on the neck of the drum, the cover, with its gasket, is

pulled firmly onto the completely flat upper surface of the neck of the drum and is pressed against it by means of a nonrelaxing lock tightener. In this manner, in accordance with the present invention, the cover can easily be placed on the drum and closed absolutely tightly and safely without difficulty by reversing and tightening of the locking ring.

What is claimed is:

l. A drum and cover therefor comprising: i a drum body portion of plastic composition having a cylindrical neck extending axially parallel to the axis of the drum,

a drawn-in portion adjacent the top of the neck forming an annular bulged-in bead of smaller diameter than the neck,

a plurality of bulge-like projections disposed circumferentially about the neck, each of said bulge-like projections having a lower surface slanting away from the outer cylindrical surface of the neck;

closure means for said drum comprising a cover havan outer cylindrical portion adapted to fit tightly over the neck of drum, said outer cylindrical portion having cut out sections adapted to fit snugly over the bulge-like projections on the neck of the drum,

an inner cylindrical portion coaxial with and of smaller diameter than the outer cylindrical portion, said two portions being connected to form an external rim and an inner annular groove,

a lip-like reinforcement on the underside of said inner portion providing a bearing surface for the bead on the neck of the drum, and

outwardly projecting reinforcements on the lower edges of the segments of the cover between the bulge-like projections on the neck of the drum, each of said reinforcements having a surface slanting away from the outer cylindrical surface of the cover;

sealing means in the bottom of the aforementioned annular groove; and

resilient locking means encircling the cover for securing said cover to the neck of drum.

2. A drum and cover according to claim 1 wherein said cover has a recessed bottom, said lip-like reinforcement extends downwardly from said bottom, and said lip-like reinforcement is bent at right angles inwardly in relation to the rim which surrounds the recessed bottom thereby narrowing the aforementioned annular groove.

3. A drum and cover according to claim 1 wherein the lower surface of each bulge-likeprojection on the neck of the drum defines an obtuse angle with the outer cylindrical surface of the neck.

4. A drum and cover according to claim 1 wherein the lower surface of each bulge-like projection bulging on the neck of the drum is slightly convex.

5. A drum and cover according to claim 1 wherein the upper surface of each reinforcing projection on the cover forms a ledge-like surface which defines an obtuse angle with the outer cylindrical surface of the cover.

6. A drum and cover according to claim 1 characterized in that the upper surface of each reinforcing projection on the cover is slightly convex.

7. A drum and cover according to claim 1 wherein the lower surfaces of the bulge-like projections on the neck of the drum and the upper surfaces of adjacent reinforcing projections on the cover together define an acute angle.

8. A drum and cover according to claim 1 wherein the resilient locking means comprises a circumferential, resilient locking ring disposed in the angle defined by the slanting lower surfaces of the bulge-like projections on the neck of the drum and the adjacent slanting upper surfaces of the reinforcing projections on the cover, said locking ring alternately and sequentially engaging said slanting surfaces to draw the cover down tightly over the neck of the drum.

9. A drum and cover according to claim 1 wherein the sealing means in the bottom of the annular groove comprises a resilient gasket.

10. A drum and cover according to claim 8 wherein the locking ring comprises a spring having a round cross section. 

1. A drum and cover therefor comprising: a drum body portion of plastic composition having a cylindrical neck extending axially parallel to the axis of the drum, a drawn-in portion adjacent the top of the neck forming an annular bulged-in bead of smaller diameter than the neck, a plurality of bulge-like projections disposed circumferentially about tHe neck, each of said bulge-like projections having a lower surface slanting away from the outer cylindrical surface of the neck; closure means for said drum comprising a cover having an outer cylindrical portion adapted to fit tightly over the neck of drum, said outer cylindrical portion having cut out sections adapted to fit snugly over the bulge-like projections on the neck of the drum, an inner cylindrical portion coaxial with and of smaller diameter than the outer cylindrical portion, said two portions being connected to form an external rim and an inner annular groove, a lip-like reinforcement on the underside of said inner portion providing a bearing surface for the bead on the neck of the drum, and outwardly projecting reinforcements on the lower edges of the segments of the cover between the bulge-like projections on the neck of the drum, each of said reinforcements having a surface slanting away from the outer cylindrical surface of the cover; sealing means in the bottom of the aforementioned annular groove; and resilient locking means encircling the cover for securing said cover to the neck of drum.
 2. A drum and cover according to claim 1 wherein said cover has a recessed bottom, said lip-like reinforcement extends downwardly from said bottom, and said lip-like reinforcement is bent at right angles inwardly in relation to the rim which surrounds the recessed bottom thereby narrowing the aforementioned annular groove.
 3. A drum and cover according to claim 1 wherein the lower surface of each bulge-like projection on the neck of the drum defines an obtuse angle with the outer cylindrical surface of the neck.
 4. A drum and cover according to claim 1 wherein the lower surface of each bulge-like projection bulging on the neck of the drum is slightly convex.
 5. A drum and cover according to claim 1 wherein the upper surface of each reinforcing projection on the cover forms a ledge-like surface which defines an obtuse angle with the outer cylindrical surface of the cover.
 6. A drum and cover according to claim 1 characterized in that the upper surface of each reinforcing projection on the cover is slightly convex.
 7. A drum and cover according to claim 1 wherein the lower surfaces of the bulge-like projections on the neck of the drum and the upper surfaces of adjacent reinforcing projections on the cover together define an acute angle.
 8. A drum and cover according to claim 1 wherein the resilient locking means comprises a circumferential, resilient locking ring disposed in the angle defined by the slanting lower surfaces of the bulge-like projections on the neck of the drum and the adjacent slanting upper surfaces of the reinforcing projections on the cover, said locking ring alternately and sequentially engaging said slanting surfaces to draw the cover down tightly over the neck of the drum.
 9. A drum and cover according to claim 1 wherein the sealing means in the bottom of the annular groove comprises a resilient gasket.
 10. A drum and cover according to claim 8 wherein the locking ring comprises a spring having a round cross section. 